Optical fiber connectors are used to optically connect one optical fiber to another. One parameter used to measure the quality of the optical fiber connection made by the optical fiber connector is the insertion loss (IL), which is a measure of how much light is lost when passing from one fiber to the other through the optical fiber connector. In some configurations, the optical fiber connector being evaluated is referred to as the device under test (DUT) and the connector to which the DUT is connected is called the reference connector or reference jumper.
Current IL measurement methods used by most optical connector manufacturers require physical contact of the end faces of the DUT and the reference connectors, or the use of an index matching fluid between them. This method is useful because it measures the insertion loss under conditions that are very similar if not identical to the conditions in the field. A problem with the contact-based measurement approach however is that when the polished ends of the fibers are brought into contact, they can suffer damage.
It would therefore be beneficial to be able to perform contact-based IL measurements in a manner that reduces or eliminates the risk of damage to the polished fiber ends.